Silicon transistors have been the core of modern day computers. They have miniaturized computers from a hall sized machine to a palm sized contraption. Companies have been cramming in millions and millions of transistors onto a single chip to increase processing power as Gordon Moore had once stated in his law. Intel has already shifted to 32nm and AMD is playing catch up. But there is only so much miniaturization possible. There exists a physical limit after which transistors just cannot be stacked up like dominoes. HP though claims to have an answer.
HP’s scientist have recently announced to the New York Times about a totally different concept which does not involve transistors rather memristors (Memory Resistors). A memristor is like any two terminal circuit element. Like any other circuit element it maintains a functional relationship between the time integrals of voltage and current. HP has utilized this piece of technology to devise a switching circuit, the basic function of a transistor.
HP’s new brainchild consists of a 50nm thick Titanium Dioxide film wedged in between two 5nm thick films, one made of Titanium and the other of Platinum. The Titanium dioxide has two areas of different densities initially. In one of the areas there is abundance of oxygen ions while the other has a depleted oxygen ion supply. When current passes through a memristor it causes a shift in the oxygen concentrations. Since this is a permanent change and is only dependent on the amount of charge passed through the device it can store values even with no current passing through the device. This is a significant upgrade over transistors which are erased clean whet shut off. The oxygen concentrations can be brought back to their initial values by passing current in the opposite direction.
Thus a large array of such memristors could function as a data storage device. HP claims to have tested these devices in their research labs and speaks highly of this new innovation. HP scientists have managed to achieve one tenth of the speed of read and write presently attained by today’s devices. Nevertheless they claim in two years time they will have a device much faster than any other flash based storage device with a storage density of upto 20GB per square centimetre. The payoff in this device is not speed rather size. The smallest transistor manufactured by Intel is 32nm whereas a single memristor could be as small as 3nm. A whopping ten times smaller! There is also the added advantage of ultra low power consumption.
HP’s scientists could well pave the way for future super computers with these new minuscule devices. Memristors score over other alternatives to silicon transistors like phase change memory in terms of switching speeds and power consumption. As the performance of these devices has already been tested in the labs there seems to be a lot of potential in HP’s claims.
